1. Field of the Invention
The present invention relates to an information input/output control device and a method therefor which displays a list of identification information indicating an information terminal device with which a functional operation can be executed in a network environment under which plural kinds of information terminals are available to be used.
2. Related Background Art
There has been conventionally no method for using a network scanner with which scanning operations are performed by a remote host device connected to a network.
Accordingly, the host device requesting a scanning operation must be fed a video image signal from a scanner connected to the host device. Alternatively, the video image signal was transferred to the host device through the network.
When the video image fed by the scanner is printed out together with the other information, such as characters, drawings etc., the scanned video image and the other information are usually synthesized in the host device requesting the printing operation and output to a printer connected to the network.
There have been the following kinds of data processing methods in a conventional server device.
(1) The video image data expanded into a bit image format in the host is transferred from the host to the printer through an exclusive use interface. The host takes care of all the interface operations with the network. This method has been mainly utilized in an intelligent host, such as a work station.
(2) The host transmits only a page description language. The printer incorporating an interpreter function converts it into a bit image format, which is so called as a network printer.
(3) The device, which converts a page description language transmitted from the host into an exclusive use bit image, further transmits the image data to a printer through an exclusive use interface.
In a printer which forms a video image, with an output video image information being generated from the input data written in page description language, in particular, in a full colour printer which can form a colour video image based on colour video image data such as RGB, red (R), green (G) and blue (B) data corresponding to each input picture element are input and converted into yellow (Y), magenta (M), cyanic (C) and black (B) data, thereby being printed with ink or developer corresponding to each colour in order to output a full colour video image.
However, in order to satisfy a video image input/output request of host computers each of which is supervised by its own different operation system (OS), a plurality of interpreters are necessitated for executing data communication processing which meets each OS so that be data processing load will become heavier on a server device, which causes an increase cost of the device.
Further, when a plurality of host computers which are connected to the network control a plurality of terminal devices, video image input/output requests created by each host computer occur irregularly and sometimes concurrently with each other. In this moment, when a preceding or waiting print or scan job exists, the succeeding print or scan job cannot precede, thereby aggravating a problem in the speed of video input/output processing.
In addition, colour terminals utilized in these kinds of networks are relatively expensive in price in comparison with monocolour terminals and interface devices utilized to interface with the host are extremely expensive in price in comparison with the monocolour devices. A main reason for this is that an enormous amount of video image data is created when a colour video image is processed. Further, data must be abstracted in transmission of a colour video image.
That is, an encoding, a coding and a vectorizing are required for video image data, character data and graphic data, respectively.
These procedures can realize the data to be described in a form independent of the output terminal device by abstracting document and video image data as much as possible, thereby eliminating the data amount. On the other hand, in the receiving side which receives the data described above, the interface device utilized for converting the above described data into bit image data most suitable for each receiving device will become complicated and expensive in price.
However, under the circumstance that the colour terminal devices are utilized, it is feared that the whole device will become very expensive if each host computer employs both of a colour interface device and a colour terminal device.
On the contrary, if a supply access to a single scanner/printer which is connected to the network by a plurality of machines is non-restrictively permitted, the request of group users cannot be satisfied who are willing to use restrictively the scanners/printers connected to the network so that an access request to the scanners/printers by the specific group users will be kept waiting for a considerably long time.
The conventional video image terminal into which a communication function is incorporated executes the scanning and printing functions in accordance with an access input order from each host. While a scanner/printer server device incorporating a memory means for storing video image input/output instructions from a plurality of users is waiting, without executing input/output procedures, with stored therein an instruction designating a specific printer or a video image input device (scanner), it happens that the designated printer or scanner becomes inoperable due to, for example, a paper feed jam of a printer or a break down of an exposure lamp.
Even though, in this case, operable terminals are available, waiting and usable, they cannot start input/output processings until the first designated terminal is recovered, because they have not been designated, which reduces remarkably efficiency of the terminal devices.
Further, terminal devices, particularly printers, have not necessarily provided high quality printing because they simply execute video image output processing in accordance with input data, such as a page description language or the like. For example, in a printer which compresses image data created by a video image generator, stores its one page of data into a video image memory, and then expands it for printing so as to cope with a high speed of the printer, it has sometimes compressed with a compression rate higher than necessary because the memory in which the compressed image data is stored is limited in capacity, which results in a quality aggravation of the video image. In other words, when the compression is performed with an adequate compression rate so as to store the compressed data in the memory in full, the aggravation can be minimized. However, in the JPEG (Joint Photographic Expert Group) compression, which is a standard compression method for a colour video image, it is difficult to predict a post-compressed data amount prior to compression if information about the colour video image which is to be compressed is not available.
As the result, the compression has been performed with a higher compression rate than necessary to securely store the compressed data, which has caused an aggravation of the video image.
Furthermore, high speed and high quality printing has not necessarily been available in printing out from a binary printer by digitizing the video image information created by a video image generator.
In digitizing, for example, it is better to use an error diffusion method with which a relatively clear-cut line can be achieved for a document having much area for characters and drawings whereas it is better to use a dither method with which a relatively short processing time for digitizing can be achieved for a document having almost all its area for images.
However, in a conventional device, since the video image processor simply forms image data, a printer has been printing using only a single digitizing method regardless of the video image.
Further in a printer in which a video image created by the video image generator is colour-converted by the video image output circuit, a high quality printing has not necessarily been achieved.
In general, it is suitable to employ a colour conversion with much more black ink to make the black colour clear in a document containing many characters and drawings therein whereas it is suitable to employ a colour conversion with less black ink to make the image naturalized in a document containing many images therein.
However, in a conventional device, since the video image output circuit simply forms image data, a printer has been printing using only a single digitizing method regardless of the video image, thereby high quality printing having not necessarily been available.
The data processing format which is described by the host varies on company by company and the Quick Draw (commercial name) type, GDI (commercial name) type and the like have been available (later will be described in detail).
There are various types of page description languages (PDL) to control a printer environment, that is, a printer, such as Post Script (commercial name), ESC/P (commercial name), LIPS (commercial name), CaPSL (commercial name) and the like.
The host executes an output information with a data format which depends on an activatable application program.
Accordingly, if the data format of the output device to be connected thereto is mismatched with that depending on the above application program, the application program must be amended in order to output the data through the output device, whereby the selection range of the output device to be connected will be narrowed.
Further, in the case of amending each application program, the developing cost for each application will become heavier, thereby decreasing the customer's interest in purchasing the application programs.